"Often retirement plans leave too many decisions up to participants, many of whom are ill-equipped to make well-informed decisions," says Ravi Venkataraman, global head of consultant relations at MFS. "Plan sponsors have a number of tools at their disposal that can help participants better invest for retirement. Creating simplified investment menus, implementing auto-enrollment and auto-escalation contribution plans, and offering professionally managed, diversified investment options will give participants the greatest chance of successfully investing for retirement."

In other words, if your 401(k) investment menu seems too complicated, get help – and complain.